Acklam Hall redevelopment due to start by August
The redevelopment of Middlesbrough's only Grade I-listed building is expected to start in August, developers say.
Planning permission was granted in June for the grounds of Acklam Hall to be used for housing, a care home and doctors' surgery.
The 17th Century stately home was last used by Middlesbrough College in 2008.
Neil Whittingham, managing director of developer Acklam Hall Ltd, said the process had been "long and slow".
Complications were caused by changes made to the health service, including the abolishment of primary care trusts.
Proposed structural changes were monitored by English Heritage.
Some wing buildings will be demolished and it is hoped a restaurant and businesses could eventually be housed in the main hall.
Marilyn Woods, from residents' group Acklam 2020, said she was "disappointed, but not surprised" by delays in redeveloping the site.
Middlesbrough councillor Shamal Biswas said: "When you are dealing with such a prestigious place you have to safeguard the future of the building."